浅谈混凝土面板堆石坝面板裂缝的原因和预防方法

重点通过介绍某水电站混凝土面板堆石坝面板在施工产生中怎样预防裂缝,及对造成裂缝原因的分析。

急性肺栓塞从预防开始

认识急性肺栓塞发病因素，总结急性肺栓塞发生的常见因素，早期采取预防措施，临床医师提高对肺栓塞的认识水平，从预防开始，减少肺栓塞的发生率和病死率。

Hepatocellular carcinoma prevention:A worldwide emergence between the opulence of developed countries and the economic constraints of developing nations

Hepatocellular carcinoma (HCC) is the fifth most common neoplasm, the major cause of death in patients with liver cirrhosis, and the third most common cause of cancer-related death in the world. The geographic distribution of HCC varies significantly and 80% of cases occur in developing countries (Far East and South Asia) where the prevalence of viral hepatitis is higher. The treatment of HCC is difficult because most patients are diagnosed when the tumour is in an advanced stage and is not amenable to potential curative therapy, thus prevention is the key to reducing HCC and its related morbidity and mortality. HCC is unique among cancers, occurring mostly in patients with a known risk factor. Ninety percent of HCCs develop in the context of chronic liver diseases and mainly in patients with cirrhosis. Viral hepatitis is the most common cause of HCC worldwide, followed by alcoholic liver disease (ALD) and other causes such as non-alcoholic fatty liver disease (NAFLD), genetic haemocromatosis (GH) and primary biliary cirrhosis in an advanced stage (Ⅲ- Ⅴ). In certain areas of the People’s Republic of China, exposure to aflatoxin and HBV infection are thought to be responsible for the extraordinary high risk of HCC. Substantial progresses in the prevention of virusl-related hepatitis (screening of blood units, use of disposable sanitary tools, HBV vaccination) have been achieved in developed countries, but in the same areas, alcohol- and dysmetabolism-related HCCs are emerging problems which require specific interventions in terms of public health measures. In developing countries, economic constraints limit the development of any program for the prevention of viral hepatitis transmission (including health education campaigns, healthcare politics, primary prevention and the improvement of hygienic and sanitary conditions). When viral liver disease is established, only a minority of patients are treated worldwide and benefit a possible preventive effect of medical treatment onHCC development. Thus the real contribution of medical treatment to HCC prevention in patients with chronic viral hepatitis is small. Great efforts are needed to identify more effective medical measures for primary and secondary prevention of HCC.

Positive Selection Analysis of VP1 Genes of Worldwide Human Enterovirus 71 Viruses

Human enterovirus 71 viruses have been long circulating throughout the world. In this study, we performed a positive selection analysis of the VP1 genes of capsid proteins from Enterovirus 71 viruses. Our results showed that although most sites were under negative or neutral evolution, four positions of the VP1 genes were under positive selection pressure. This might account for the spread and frequent outbreaks of the viruses and the enhanced neurovirulence. In particular, position 98 might be involved in neutralizing antibodies, modulating the virus-receptor interaction and enhancing the virulence of the viruses. Moreover, both positions 145 and 241 might correlate to determine the receptor specificity. However, these positions did not display much difference in amino acid polymorphism. In addition, no position in the VP1 genes of viruses isolated from China was under positive selection.

Survivin:Potential role in diagnosis,prognosis and targeted therapy of gastric cancer

Survivin is a protein that is highly expressed in a vast number of malignancies,but is minimally expressed in normal tissues. It plays a role as an inhibitor of cell death in cancer cells,thus facilitating the growth of these cells. In the case of gastric cancer,survivin is over-expressed in tumor cells and plays a role in the carcinogenesis process. Several studies on gastric cancer have indicated that there is a relationship between survivin expression and the ultimate behavior of the carcinoma. Since the expression pattern of survivin is selective to cancer cells,it has been described as an "ideal target" for cancer therapy. Currently,several pre-clinical and clinical trials are on-going to investigate the effects of interfering with survivin function in cancer cells as a biologic therapy. Survivin is a potentially significant protein in the diagnosis,prognosis and treatment of gastric tumors.

Prevention of hepatotoxicity due to anti tuberculosis treatment: A novel integrative approach

AIM： To evaluate the ability of Curcuma Ionga （CL） and Tinospora cordifolia （TC） formulation to prevent anti-tuberculosis （TB） treatment （ATT） induced hepatotoxicity. METHODS： Patients with active TB diagnosis were randomized to a drug control group and a trial group on drugs plus an herbal formulation. Isoniazid, rifampicin, pyrazinamide and ethambutol for first 2 mo followed by continuation phase therapy excluding Pyrazinamide for 4 mo comprised the anti-tuberculous treatment. Curcumin enriched （25%） CL and a hydro-ethanolic extract enriched （50%） TC 1 g each divided in two doses comprised the herbal adjuvant. Hemogram, bilirubin and liver enzymes were tested initially and monthly till the end of study to evaluate the result. RESULTS： Incidence and severity of hepatotoxicity was significantly lower in trial group （incidence： 27/192 vs 2/316, P 〈 0.0001）. Mean aspartate transaminase （AST） （195.93 ± 108.74 vs 85 ± 4.24, P 〈 0.0001）, alanine transaminase （ALT） （75.74 ± 26.54 vs 41 ± 1.41, P 〈 0.0001） and serum bilirubin （5.4 ±3.38 vs 1.5 ±0.42, P 〈 0.0001）. A lesser sputum positivity ratio at the end of 4 wk （10/67 vs 4/137, P = 0.0068） and decreased incidence of poorly resolved parenchymal lesion at the end of the treatment （9/152 vs 2/278, P = 0.0037） was observed. Improved patient compliance was indicated by nil drop-out in trial vs 10/192 in control group （P 〈 0.0001）. CONCLUSION： The herbal formulation prevented hepatotoxicity significantly and improved the disease outcome as well as patient compliance without any toxicity or side effects.

Mechanisms of action of leptin in preventing gastric ulcer

To investigate the effects of leptin （1-20μg/kg） on acidified ethanol （AE）- and indomethacin （Indo）-induced gastric lesions in rats and compare it with ranitidine, lansoprazole, and omeprazole and to determine its mechanisms of actions.METHODS： Gastric ulcers, which were approximately 1 mm in width, formed in the glandular portion of the gastric mucosa produced by oral administration of either AE or Indo were taken as ulcer index. The inhibitory effect of subcutaneous administration of leptin, two proton pump inhibitors （PPIs） lansoprazole and omeprazole, or H2-receptor antagonist ranitidine 30 min before AE or Indo was evaluated.A radioimmunoassay was used to determine the PGE2 concentration in the homogenate of the glandular portion of the stomach. We performed histological study of the glandular stomach for the evaluation of total, acidic, and sulfated mucus content.RESULTS： Subcutaneous administration of leptin, two PPI slansoprazole and omeprazole or H2-receptor antagonist ranitidine 30 min before AE or Indo produced a dosedependent and reproducible inhibition of gastric ulcers （GUs）. This inhibition was found to be more potent than other antagonists used. In N^G-nitro L-arginine methyl ester （L-NAME）-pretreated animals, the ulcer prevention ability of leptin in AE-induced ulcer was significantly reduced,compared to rats without L-NAME pretreatment. However,the ulcer prevention ability of leptin was not altered by L-NAME treatment in Indo-induced ulcers. Leptin produced a dose-dependent increase in PGE2 level in the gastric glandular tissues. Leptin also increased mucus secretion.CONCLUSION： The results of the present study show that leptin inhibits GU formation by AE or Indo in a dosedependent and reproducible manner in rats. The results also suggest that leptin prevents ulcer formation by increasing the activities of the cyclo-oxygenase and/or nitric oxide pathways and by increasing mucus secretion.

Avoiding misdiagnosing an early intrauterine pregnancy as an ectopic pregnancy

In women at risk for an ectopic pregnancy, every effort should be made to exclude the presence of an intrauterine pregnancy before embarking on an irreversible treatment for ectopic pregnancy. The diagnosis of ectopic pregnancy, unless directly visualized with transvaginal ultrasound, is made with the exclusion of an intrauterine pregnancy. Measurement of human chorionic gonadotrophin and progesterone levels, and transvaginal ultrasound are the tools used to evaluate early pregnancy. In women at risk for an ectopic pregnancy, every effort should be made to exclude the presence of an intrauterine pregnancy before embarking on an irreversible treatment course. Methotrexate is an antimetabolite that inhibits DNA synthesis and repair and cell replication. It is administered to ostensible destroy a pregnancy, especially ectopic pregnancies. When administered to an intrauterine pregnancy, embryonic death and missed abortion is the most common result, but early embryos that survive this exposure are likely to have multiple anomalies. The mistaken administration of methotrexate to an intrauterine pregnancy is made because of misinterpretation of the discriminatory zone of human chorionic gonadotropin(h CG), misinterpretation of early h CG serum levels, misinterpretation of early transvaginal ultrasound images, and failure to clinically correlate h CG levels and ultrasound findings.

Rock burst induced by roof breakage and its prevention

Based on the research on rock burst phenomenon induced by the breakage of thick and hard roof around roadways and working faces in coal mines, a criterion of rock burst induced by roof breakage （RBRB） was proposed and the model was built. Through the model, a method calculating the varied stresses induced by roof breakage in support objects and coal body was proposed and a unified formula was derived for the calculation of stress increment on support objects and coal body under different breaking forms of roof. Whilst the formula for calculating dynamic load was derived by introducing dynamic index Kd. The formula was verified in Huating Mine by stress measurement. According to the formula for stress increment calculating, the sensitivities of dynamic load parameters were further studied. The results show that the thickness and breaking depth of roof, width of support objeet are the sensitive factors. Based on the discussion of the model, six associated effective methods for rock burst prevention are obtained.

如何正确处理初中生早恋问题

中学时代正是长身体、长知识的黄金时期，谈情说爱必然会分散精力，影响学业进步，影响身心健康发展。一旦发生挫折，就会给自己带来更大的烦恼和痛苦，甚至会造成严重后果，给自己带来终身遗憾。

Venous thromboembolism prophylaxis in hospitalized elderly patients： Time to consider a ＇MUST＇ strategy

Venous thromboembolism （VTE） is the commonest cause of preventable death in hospitalized patients. Elderly patients have higher risk of VTE because of the high prevalence of predisposing co-morbidities and acute illnesses. Clinical diagnosis of VTE in the elderly patient is particularly difficult and, as such, adequate VTE prophylaxis is of pivotal importance in reducing the mortality and morbidities of VTE. Omission of VTE prophylaxis is, however, very common despite continuous education. A simple way to overcome this problem is to implement universal VTE prophylaxis for all hospitalized elderly patients instead of selective prophylaxis for some patients only according to individual＇ s risk of VTE. Although pharmacological VTE prophylaxis is effective for most patients, a high prevalence of renal impairment and drug interactions in the hospitalized elderly patients suggests that a multimodality approach may be more appropriate. Mechanical VTE prophylaxis, including calf and thigh compression devices and/or an inferior vena cava filter, are often underutilized in hospitalized elderly patients who are at high-risk of bleeding and VTE. Because pneumatic compression devices and thigh length stockings are virtually risk free, mechanical VTE prophylaxis may allow early or immediate implementation of VTE prophylaxis for all hospitalized elderly patients, regardless of their bleeding and VTE risk. Although the cost-effectiveness of this Multimodality Universal STat （＇MUST＇） VTE prophylaxis approach for hospitalized elderly patients remains uncertain, this strategy appears to offer some advantages over the traditional ＇selective and single-modal＇ VTE prophylaxis approach, which often becomes ＇hit or miss＇ or not implemented promptly in many hospitalized elderly patients. A large clustered randomized controlled trial is, however, needed to assess whether early, multimodality, universal VTE prophylaxis can improve important clinical outcomes of hospitalized elderly patients.

Testing with high density resistivity method in prevention and cure for mine water disaster and its applied effect

The detecting examples using the high density resistivity method, about the evaluation of containing water characteristic from the floor rock and the height of overburden failure, were given. It expresses that the high density resistivity method has good effect with strong maneuverability and continuous observing section during the prevention and cure for mine water disaster. At the same time, the article pointed out that the study of space data inversion and dynamic watching technology about the high density resistivity method must be enhanced in the future because of special condition of data collecting in mine.

A systematic review: How to choose appropriate health-related quality of life (HRQOL) measures in routine general practice?

In more recent times, health-related quality of life (HRQOL) measurements have formed an important part of as- sessing the quality of routine care in general practice. For a measure to have clinical usefulness it must not only be valid, appro- priate, reliable, responsive, and capable of being interpreted, but it must also be simple, fast to complete, easy to score, and provide useful clinical data. The Two-step method of choosing appropriate measures is introduced. Then through comparison of generic instruments with disease-specific instruments, we can conclude that sometimes a combination of generic and disease-specific HRQOL measures may be more appropriate for monitoring changes in a patient’s health status due to an intervention.

Human herpesvirus 6 infections after liver transplantation

Human herpesvirus 6(HHV-6) infections occur in > 95% of humans.Primary infection,which occurs in early childhood as an asymptomatic illness or manifested clinically as roseola infantum,leads to a state of subclinical viral persistence and latency.Reactivation of latent HHV-6 is common after liver transplantation,possibly induced and facilitated by allograft rejection and immunosuppressive therapy.Since the vast majority of humans harbor the virus in a latent state,HHV-6 infections after liver transplantation are believed to be mostly due to endogenous reactivation or superinfection(reactivation in the transplanted organ).In a minority of cases,however,primary HHV-6 infection may occur when an HHV-6 negative individual receives a liver allograft from an HHV-6 positive donor.The vast majority of documented HHV-6 infections after liver transplantation are asymptomatic.In a minority of cases,HHV-6 has been implicated as a cause of febrile illness with rash and myelosuppression,hepatitis,pneumonitis,and encephalitis after liver transplantation.In addition,HHV-6 has been associated with a variety of indirect effects such as allograft rejection,and increased predisposition and severity of other infections including cytomegalovirus(CMV),hepatitis C virus,and opportunistic fungi.Because of the uncommon nature of the clinical illnesses directly attributed to HHV-6,there is currently no recommended HHV-6-specific approach to prevention.However,ganciclovir and valganciclovir,which are primarily intended for the prevention of CMV disease,are also active against HHV-6 and may prevent its reactivation after transplantation.The treatment of established HHV-6 disease is usually with intravenous ganciclovir,cidofovir,or foscarnet,complemented by reduction in the degree of immunosuppression.This article reviews the current advances in the pathogenesis,clinical diagnosis,and therapeutic modalities against HHV6 in the setting of liver transplantation.

Causes Leading to Formation of Shot Cokes and Measures for Its Prevention in Super Viscous Oil Delayed Coking Unit

Shot cokes are frequently formed in the delayed coking unit treating the super viscous oil at PetroChina＇s Liaohe Petrochemical Company. Considerable work has been carded out to avoid the formation of shot cokes. The test results obtained have shown that the property of super viscous oil has played a key role in the formation of shot cokes. After adjusting and optimizing the process indices the operating regime of the delayed coking unit at a throughput of 118t/h of the super viscous oil is specified as follows： a reaction temperature of 498-502℃, a reaction pressure of 0.17-0.25 MPa, a recycle ratio of 0.5-0.6 and a fractionation tower bottom temperature of 355-365 ℃. In the meantime, the delayed coking process has adopted measures to enhance pre-fractionation of the feedstock to rationally remove light fractions and maintain a steady gas velocity in order to avoid the formation of shot cokes.

Selection Pressure on Haemagglutinin Genes of H9N2 Influenza Viruses from Different Hosts

Positive selection and differential selective pressure analyses were carried out to study Haemagglutinin (HA) genes of H9N2 influenza viruses from different hosts in this paper. Results showed that, although most positions in HAs were under neutral or purifying evolution, a few positions located in the antigenic regions and receptor binding sites were subject to positive selection and some of them were even positively selected at the population level. In addition, there were always some positions differentially selected for viruses from different hosts. Both selection pressure working on HA codons and positions differentially selected might account for the extension of the host range and adaptations to different hosts of H9N2 influenza viruses.

The Use of Postoperative Serum HS-AFP and GGTⅡfor Judgment of the Prognosis for Hepatocellular Carcinoma patients

OBJECTIVE To investigate the clinical value of hepatoma-specific alpha-fetoprotein （HS-AFP） and gamma-glutamyltransferase Ⅱ （GGT Ⅱ） for judgment of postoperative prognosis of patients with hepatocellular carcinoma （HCC）. METHODS HS-AFP was separated and determined using native polyacrylamide electrophoresis with a discontinuous buffer system and Western blots. GGT Ⅱ was separated with native polyacrylamide electrophoresis with a discontinuous buffer system and detected by enzyme staining. Forty cases with HCC underwent serial determination of HS-AFP and GGT Ⅱ before and after radical excision. The correlations were analyzed between the two indices and survival time. RESULTS In the 40 cases with HCC, before radical excision the positive rates of HS-AFP and GGT II were 57.5% and 67.5% respectively, with the positive rate of combined HS-AFP and GGT Ⅱ reaching 80.0%. After operation, the recurrence and metastasis rate in the groups with positive HS-AFP and GGT Ⅱ were 90.9% and 58.8% respectively, while in the groups with negative HS-AFP and GGT Ⅱ the rates were 20.7% and 26.1% respectively. Recurrence and metastasis occurred in all cases with both postoperative positive HS-AFP and GGT Ⅱ but only in 9.5% of the cases in whom both postoperative HS-AFP and GGT Ⅱ were negative. Univariate analysis revealed that postoperative HS-AFP and GGT Ⅱ were related to the prognosis in HCC. CONCLUSION Postoperative serum HS-AFP and GGT Ⅱ are very useful in predicting the prognosis of HCC patients.

Genome Sequencing and Phylogenetic Analysis of Three Avian Influenza H9N2 Subtypes in Guangxi

Three isolates of H9N2 Avian Influenza viruses (AIV) were isolated from chickens in Guangxi province. Eight pairs of specific primers were designed and synthesized according to the sequences of H9N2 at GenBank. phylogenetic analysis showed a high degree of homology between the Guangxi isolates and isolates from Guangdong and Jiangsu provinces, suggesting that the Guangxi isolates originated from the same source. However, the eight genes of the three isolates from Guangxi were not in the same sublineages in their respective phylogenetic trees, which suggests that they were products of natural reassortment between H9N2 avian influenza viruses from different sublineages. The 9 nucleotides ACAGAGATA which encode amino acids T, G, I were absent between nucleotide 205 and 214 in the open reading frame of the NA gene in the Guangxi isolates. AIV strains that infect human have, in their HA proteins, leucine at position 226. The analysis of deduced amino acid sequence of HA proteins showed that position 226 of these isolates contained glycine instead of leucine, suggesting that these three isolates differ from H9N2 AIV strains isolated from human infections.

A strategy for rock/coal outburst prevention

The current practice of rock/coal outburst monitoring, prevention and control was reviewed. The uncertainty of major factors contributing to the occurrence of such hazards and the complexicity of mining conditions surrounding the occurrence were analyzed. A strategic concept for rock/coal outburst prevention was introduced. The objective is to identify the bursting potential in an area, rather than predicting the bursting, by introducing a multi- dimension index model： potential-of-bursting （POB）, taking into consideration major contributing factors. In application, once the index has passed certain critical level indicating high risk, actions must be taken to reduce the bursting potential and to effectively prevent the hazard from occurring. A conceptual 2D model involving stress and methane pressure was described to demonstrate the methodology for determining the POB. However in practice, a POB model has to be established through experiments, field monitoring and calibration against case studies. To achieve this objective, coordinated research and international collaboration will be needed.

Postpartum intrauterine device contraception: A review

AIM： To review the safety （infection, perforation） and efficacy （expulsion, continuation rates, pregnancy） of intrauterine device （IUD） insertion in the postpartum period. METHODS： MEDLINE, PubMed and Google Scholar were searched for randomized controlled trials and prospective cohort studies of IUD insertions at different times during the postpartum period. Time of insertion during the postpartum period was documented speci-fically, immediate post placenta period （within 10 min）, early post placenta period （10 min to 72 h）, and de-layed/interval period （greater than 6 wk）. Other study variables included mode of delivery, vaginal vs cesarean, manual vs use of ring forceps to insert the IUD. RESULTS： IUD insertion in the immediate postpartum （within 10 min of placental delivery）, early postpartum （10 min up to 72 h） and Interval/Delayed （6 wk onward） were found to be safe and effcacious. Expulsion rates were found to be highest in the immediate postpartum groups ranging from 14% to 27%. Immediate post placental insertion found to have expulsion rates that ranged from 3.6% to 16.2%. Expulsion rate was significantly higher after insertion following vaginal vs cesarean delivery. The rates of infection, perforation and unplanned pregnancy following postpartum IUD insertion are low. Method of insertion such as with ring forceps, by hand, or another placement method unique to the type of IUD did not show any signifcant difference in expulsion rates. Uterine perforations are highest in the delayed/interval IUD insertion groups.Breastfeeding duration and infant development are not affected by delayed/interval insertion of the non-hormonal （copper） IUD or the Levonorgestrel IUD. Timing of the Levonorgestrel IUD insertion may affect breastfeeding. CONCLUSION： IUD insertion is safe and efficacious during the immediate postpartum, early postpartum and delayed postpartum periods. Expulsion rates are highest after vaginal delivery and when inserted during the immediate postpartum period. IUD associated infection rates were not increased by insertion during the postpartum period over interval insertion rates. There is no evidence that breastfeeding is negatively affected by postpartum insertion of copper or hormone-secreting IUD. Although perforation rates were higher when inserted after lactation was initiated. Randomized controlled trials are needed to further elucidate the consequence of lactation on postpartum insertion. Despite the concerns regarding expulsion, perforation and breastfeeding, current evidence indicates that a favorable risk beneft ratio in support of postpartum IUD insertion. This may be particularly relevant for women for whom barriers exist in achieving desired pregnancy spacing.